1. Field of the Invention
The present invention relates to a radiation-sensitive resin composition.
2. Discussion of the Background
Chemically amplified radiation-sensitive resin compositions generate an acid upon irradiation with an electron beam or far ultraviolet ray typified by KrF excimer laser or ArF excimer laser at a light-exposed site, and a chemical reaction that proceeds with the acid as a catalyst allows the difference in dissolution rates in developing solutions to be produced between the light-exposed site and the light-unexposed site, thereby enabling resist patterns to be formed on the substrate.
For example, as lithography materials for ArF excimer laser that enable microfabrication with light at shorter wavelengths, a resin composition containing as a constitutional component a polymer having in the skeleton an alicyclic hydrocarbon that does not exhibits significant absorption in the area of 193 nm, particularly a polymer having a lactone skeleton in the structure unit has been used.
A nitrogen-containing compound is added to the radiation-sensitive resin composition as described above for the purpose of attaining process stability (see Japanese Unexamined Patent Application, Publication Nos. H5-232706, H5-249683 and H5-158239). In addition, for particularly improving lithographic performance of independent patterns, addition of a nitrogen compound having a specific carbamate group has been also studied (see Japanese Unexamined Patent Application, Publication Nos. 2001-166476 and 2001-215689).
However, according to the current situation in which miniaturization of the resist pattern advances to a level of line widths being no greater than 90 nm, not only just improvement of fundamental characteristics such as improvement of resolving ability, expansion of focus latitude and exposure latitude (EL), and improvement of rectangularity of the pattern, but also other performance have been demanded. For example, as one of miniaturization techniques of the resist pattern at present, putting liquid immersion lithography into practical applications has been promoted, and a resist material being applicable also to the liquid immersion lithography has been demanded. Specifically, development of a material that satisfies demand characteristics such as an improvement of MEEF (Mask Error Enhanced Factor) that is a marker representing mask error tolerance has been desired.